vSAN Witness Appliance is very useful when you are going for 2 Node vSAN Configuration or vSAN Stretched Cluster configuration. The vSAN Witness Host is a dedicated ESXi host, which may be a physical ESXi host or vSAN Witness Appliance, whose purpose is to host the Witness component of vSAN objects or virtual machine objects.
Primary role of vSAN Witness host is to be a witness in 2 Node vSAN cluster & vSAN Stretched Cluster configuration to avoid split brain scenarios. It is used to decide the virtual machine objects availability in the Stretched vSAN Cluster & 2 Node vSAN Cluster. The witness host must be managed by the same vCenter Server managing the vSAN Cluster. There must be connectivity between vCenter Server and the witness host in the same fashion as vCenter controlling other vSphere hosts.
vSAN data traffic requires a low-latency, high-bandwidth link. Witness traffic can use a high-latency, low-bandwidth and routable link. To separate data traffic from witness traffic, you can configure a dedicated VMkernel network adapter for vSAN witness traffic.
Networking requirements for vSAN Witness Appliance:
- Data site to witness traffic connection require a minimum bandwidth of 2 Mbps for every 1,000 vSAN components.
- Two-host vSAN clusters must have less than 500 ms RTT.
- Stretched clusters with less than 11 hosts per site must have less than 200 ms RTT. Stretched clusters with 11 or more hosts per site must have less than 100 ms RTT.
- Data traffic and witness traffic must use the same IP version.
vSAN Witness Appliance can be physical ESXi host or the virtual appliance. It is recommended to use the virtual appliance. In this post we have used virtual appliance.
So let’s see How to Deploy vSAN Witness Appliance Step by Step:
First you need to download vSAN Witness Appliance from VMware Portal. It comes as an OVA file.Go to VMware Portal, Select your vSAN Witness Appliance version & Download.
Select your Datacenter or Cluster. Right click & Deploy OVF Template.
Select Local file & browse to vSAN Witness Appliance which you have downloaded.
Provide the Name for vSAN Witness VM.
Select the Datacenter & folder where you want to deploy vSAN Witness Appliance. Click Next.
Review Details of vSAN Witness Appliance & click Next.
Read & Accept the license agreement. Click Next.
Choose the deployment configuration based on your environment. Click Next.
Select the Storage location for vSAN Witness Appliance deployment. Click Next.
Select the Network for vSAN witness appliance.
Set the root password for vSAN Witness Appliance. This will be used for Network configuration of your vSAN witness host. Click Next.
Review all the configuration & click Finish to start deployment.
It will take some time to deploy vSAN Witness Appliance.Once it is deployed successfully, you will see a VM.
So using this way you can easily deploy vSAN Witness Appliance in your environment.
In the next post we will see on How to Add vSAN Witness Appliance into vCenter & review network configuration of vSAN Witness Host.
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Information source: VMware vSAN Documentation.